1. Field of the Invention
This invention relates to surgical instrumentation and more particularly to an instrument and method for retracting or repositioning an anatomic structure defining a lumen in an insufflated workspace to facilitate an endoscopic surgery. The invention disclosed herein is related to a co-pending and commonly invented application which is incorporated herein by reference: "Surgical Instrument and Method for Intraluminal Retraction of an Anatomic Structure" filed Jun. 24, 1994, Ser. No. 08/265,577, now U.S. Pat. No. 5,558,665 issued Sep. 24, 1996.
2. Description of Prior Art
In a "minimally invasive" endoscopic surgery in an insufflated abdominal cavity, it has been found that some procedures are complex and time-consuming because of difficulties in retracting or repositioning an anatomic structure with elongate instruments (e.g., graspers). Since all retracting and dissecting instruments are introduced through cannulas that are in stationary positions in the abdominal wall, it often is difficult to retract a structure to access the site of the actual dissection. Often it is necessary to introduce retracting instruments from multiple locations and on occasion, the retracting instruments must cross the region of dissection, obstructing the surgeon's view and interfering with the dissecting instruments. Further, due to its small diameter, an endoscopic retracting instrument cannot apply retraction forces over a broad surface of a structure thus causing retraction forces to be localized to a small surface area which is undesirable. For example, the jaws of a grasper may damage tissue as it grips and pulls on the exterior wall of an anatomic structure.
An illustrative example of a procedure that is difficult to perform endoscopically is a colectomy. Before resecting a portion of the colon, the surgeon must mobilize the colon by dissecting the mesentery that enfolds the colon and also by dividing blood vessels and other connective tissues that adhere to the colon. Utilizing endoscopic graspers as is currently practiced, it is difficult to adequately lift and retract the colon to access all tissues surrounding the colon that must be dissected. The graspers may damage portions of the exterior wall of the colon in regions that are not resected. The surgeon must rely on assistants to handle the retracting instruments while he manipulates the dissecting instruments. Current practice typically requires five cannulas or access ports to accommodate the retracting and dissecting instruments which is an undesirably large number. There is therefore a need for new instruments and methods for retracting an anatomic structure defining a lumen in an insufflated workspace and more particularly for retracting a colon to facilitate a colectomy.